First report of Halomicrobium mukohataei in Mexico and its biological activity

Haloarchaea produce metabolites of biotechnological importance and grow in hypersaline environments such as coastal lagoons, marine solar salterns, natural brines, and salt lakes. Haloarchaeal compounds from hypersaline environments in Mexico have been scarcely studied. This research aimed to identify a haloarchaea isolate and evaluate the antioxidant, antimicrobial, and cytotoxic properties of the culture’s biomass pigments (BPs) and supernatant pigments (SPs). One extremely halophilic archaeal strain designated AS8 was isolated from brine samples of the Bahía de Lobos coastal lagoon, Sonora, and identified as Halomicrobium mukohataei based on analyses of the 16S rRNA gene. The SPs showed the best free radical scavenging activity on DPPH and ABTS assays, with 74 and 67% inhibition values, respectively. The extracts also showed significant antibacterial activity against Gram-positive and Gram-negative bacteria with inhibition halos between 7 to 17 mm. Cytotoxic activity of extracts using nauplii of Artemia salina showed CL ₅₀ 850 µg/mL to SPs and > 1000 µg/mL to BPs. This work represents the first isolation study of H. mukohataei from Bahía de Lobos lagoon. Likewise, H. mukohataei is an alternative source of natural pigments with antioxidant, antimicrobial, and cytotoxic properties, which have potential in biomedical applications and the development of new drugs.